In a vehicular alternator disclosed in JP-B2-2927288 (U.S. Pat. No. 5,998,903), a winding of a stator is constructed of a plurality of U-shaped conductor segments. The U-shaped conductor segments are inserted in slots of a stator core from an axial end of the stator core. Ends of the U-shaped conductor segments are connected at an opposite axial end of the stator core.
In this kind of stator core, small gaps are required between the conductor segments and inside walls defining the slots to reduce resistance therebetween at the time of installation of the conductor segments. However, if the conductor segments are arranged in the slots without any limitations, the conductor segments are less likely to make contact with the inside walls, or likely to lean against and contact only one side of the inside walls.
In the case that the conductor segments do not make contact with the inside walls of the slots, efficiency of heat transfer from the conductor segments to the stator core decreases, so temperature of the conductor segments increases. As a result, it is likely that power output will decrease. On the contrary, in the case that the conductor segments lean to one side and contact only one of the inside walls, teeth of the stator core, on which the conductor segments are not leant, easily vibrates. As a result, magnetic noise increases due to an increase in magnetic vibrations.